This application relates to ultra-thin films, and to apparatus and methods for making such films. The invention is particularly applicable to self-assembling molecular films and will be described with particular reference thereto. However, it will be appreciated that the invention has broader aspects and can be used for making other types of films, such as polymer thin films.
Known techniques for making thin films, such as the conventional Langmuir-Blodgett technique, Katharine B. Blodgett, J. Am. Chem. Soc.; (1935), 57, 1007-1022, involve dropping a solution of film-forming substrate and solvent on the surface of water, and letting the solvent evaporate. This leaves behind the amphiphilic molecules to self-assemble on the surface of water to form a film, which is then compressed to align the molecules in the film. This film has certain fixed domains and cannot be manufactured in a continuous, unbroken state.
Another technique disclosed in U.S. Pat. No. 4,765,939 involves dropping a solution of film-forming polymer and solvent on the surface of water, and allowing the solvent evaporate to air. This leaves behind a thin film membrane of the polymer formed on the surface of water. All these previous techniques for making thin films or membranes containing amphiphilic molecules or polymers are such that the molecules are arranged in random disorientation.